1. Field of the Invention
The present invention relates to an optical disk apparatus that records and reproduces information on and from an optical disk, as well as a method for controlling the optical disk apparatus, and in particular, to an optical disk apparatus that automatically determines a standard for the optical disk.
2. Description of the Related Art
As is well known, techniques for densely recording information have been promoted in recent years. Optical disks having a recording capacity of 4.7 GB (Giga Bytes) in one layer of one side have been put to practical use.
Optical disks of this kind include, for example, a reproduction-only DVD-ROM (Digital Versatile Disk-Read Only Memory), a rewritable DVD-RAM (Random Access Memory), a DVD-RW (Rewritable), a +RW, and a recordable DVD-R (Recordable), which conform to various standards.
An optical disk apparatus that can execute recording and reproduction on optical disks conforming to several types of standards comprises a function utilizing the fact that the light reflectance of the optical disk varies depending on the standard. This function automatically determines the standard for the optical disk installed to regulate each section of the optical disk apparatus and change settings on the basis of the result of the determination.
Even when conforming to the same standard, current rewritable optical disks are further classified into plural types on the basis of the characteristics of a recording film used in the disk.
Specifically, there are two types of rewritable optical disks. One of them has a high light reflectance and records data after inverting (initializing) a characteristic of a recording film so that the film, which otherwise photoelectrically converts reflected light into an H (High) level, photoelectrically converts the reflected light into a L (Low) level (this type of optical disk will hereinafter be referred to as an L-H medium). The other has a low light reflectance and records data after inverting (initializing) the characteristic of the recording film so that the film, which otherwise photoelectrically converts the reflected light into the L level, photoelectrically converts the reflected light into the H level (this type of optical disk will hereinafter be referred to as an H-L medium).
Thus, it is important to have a function for not only determining a basic standard such as the DVD-RAM, DVD-RW, and +RW but also automatically determining whether each of the rewritable optical disks conforming to the same standard is an L-H or H-L medium to regulate each section of the optical disk apparatus, and change settings.
Jpn. Pat. Appln. KOKAI Publication No. 2001-266367 discloses a configuration that executes a focus search on an optical disk installed to measure the light reflectance of the optical disk on the basis of a focus error signal obtained. The configuration thus determines whether the disk is a CD (Compact Disk)-ROM, a CD-R, or a CD-RW to switch recording and reproducing circuits in accordance with the result of the determination.
This publication does not describe the automatic determination of the type of rewritable optical disk conforming to the same standard, the type of which is based on the characteristic of the recording film used.